Boundary Value Analysis (BVA) and Equivalence Partitioning (EP) testing


Boundary Value Analysis (BVA) and Equivalence Partitioning (EP) are two well-known black-box testing techniques used in software testing services in the UK. These techniques ensure comprehensive test coverage and aids in identifying potential defects in software applications.

These techniques are useful for parameterised input fields, where input values vary within specific ranges or categories. They are also used to improve the efficiency and thoroughness of testing, particularly for input-driven functionalities. Let’s explore each technique in detail:

Equivalence Partitioning (EP)

Definition: Equivalence Partitioning is a testing technique that divides the input space of a software component or system into partitions or classes of equivalent input values. The goal is to test representative values from each partition because it is assumed that if one value in a partition behaves a certain way, other values in the same partition will behave similarly. EP is commonly used to reduce the number of test cases while still achieving effective test coverage.


  • Identify Input Conditions: Understand the input conditions or requirements for the software module you are testing.
  • Divide Inputs into Classes: Divide the inputs into groups or partitions. These groups should be such that the software behaves the same way for any input within the same partition.
  • Select Representative Values: From each partition, select a representative value for testing. It is enough to select one value from each partition as they should produce similar results.
  • Test the Representative Values: Use the selected values for testing. This significantly reduces the number of test cases needed to achieve good coverage.


  • It reduces the total number of test cases needed to achieve good coverage.
  • It ensures that each class of input is adequately tested.
  • Example: If a software function accepts values from 1 to 100, you might partition this range into four classes: 1-10, 11-50, 51-90, and 91-100. Then, you’d choose one value from each class for testing.

Boundary Value Analysis (BVA)

Definition: Boundary Value Analysis is a testing technique that focuses on the boundary or edge values of input ranges. It’s based on the assumption that errors often occur near the extremes of input ranges. The idea is to test values at or near the boundaries of equivalence partitions because defects are more likely to occur in these areas.


  • Identify Input Boundaries: Identify the minimum and maximum values that the software can accept for a given input.
  • Select Boundary Values: Choose values that are just inside and just outside the identified boundaries.
  • Test the Boundary Values: Use these selected values for testing.


  • It targets areas where errors are more likely to occur.
  • It provides thorough testing without an exhaustive number of test cases.
  • Example: If a software function accepts values from 1 to 100, you’d focus on testing values like 0, 1, 2, 99, 100 and 101.

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  • In Boundary Value Analysis we identify the errors at the boundaries of input data, whereas in Equivalence Partitioning the input data is divided into partitions of valid and invalid values.
  • Equivalence Partitioning is more concerned with grouping inputs that should produce similar results, while Boundary Value Analysis focuses on testing the boundaries of input ranges.
  • Boundary Value Analysis help decreasing the testing time due to a lesser number of test cases from infinite to finite, whereas Equivalence Partitioning reduce the number of test cases to a defined list of testable test cases covering maximum possibilities.

Remember, these techniques are most effective when used in conjunction with other testing methods and should be applied based on the specific requirements and characteristics of the software being tested.

Benefits of these techniques

  • Effective Test Coverage: EP and BVA help ensure that various input scenarios are tested without an exhaustive number of test cases, making testing more efficient.
  • Defect Detection: By focusing on equivalence classes and boundary values, these techniques are effective at identifying defects that might go unnoticed with random or ad-hoc testing.
  • Documentation: EP and BVA provide clear guidelines for test case selection, which can be documented and shared with the testing team, making testing more structured and repeatable.

In summary, Equivalence Partitioning and Boundary Value Analysis are systematic and structured approaches to bespoke software development, helping testers design effective test cases that provide good coverage while focusing on critical input values and boundaries. These techniques are particularly valuable in situations where input parameters have defined ranges or categories.


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